Many agricultural processes require the delivery of a granular material, such as seed, fertilizer, and the like, from a bulk storage tank toward an outlet or secondary containment system. The granular material is often motivated pneumatically through a series of lines. The flow of granular material through the lines is typically classified as one of two general types, specifically, the granular material may be motivated in a dilute phase flow or in a dense phase flow. During dilute phase flow, the volume percentage of air in the line is much greater relative to the volume percentage of granular material. Alternatively, during dense phase flow the relative ratio is reversed, meaning that a greater volume percentage of granular material is motivated through the line by a lower volume percentage of air.
In certain dense phase flow applications, the bulk storage tank(s) are pressurized relative to the ambient environment to provide a motivating force to urge the granular material from the bulk storage tank through the lines. In an alternative dense phase flow application, an induction system is used to transfer the granular material from the bulk storage tank and into the pressurized dense phase delivery system. For example, the granular material is mechanically extracted from the bulk storage tank (generally maintained at approximately atmospheric pressure) into a primary containment tank. The primary containment tank is pressurized relative to the ambient environment to again provide a motivating force to urge the granular material through the lines.
Regardless of the system used to motivate the granular material into the delivery system, the distribution of the granular material through the lines may be managed by various valves, regulators, and the like that control and direct the level of granular material flowing into downstream secondary containments. However, the use of these various control mechanisms may present several substantial considerations and challenges. For example, in the agricultural context, most dense phase distribution systems must be efficient because an agricultural vehicle/implement has inherent power supply limitations, be it hydraulic, pneumatic, electric, and the like. Therefore, wasteful and inefficient use of these power supplies is generally avoided. Moreover, most granular material is susceptible to damage caused by the transfer process. For example, the granular material (e.g., seed) may be damaged by excessive forces encountered by the control valving or mechanism. Additionally, efficient dense phase flow is aided by providing a continual supply of granular material. This is partially achieved through the use of valves that are capable of controlling the flow of granular material over repeated cycles without clogging or binding.
In view of at least the preceding considerations, a need exists for an efficient, reliable valve for controlling the continual flow of granular material while minimizing damage to the granular material.